Bispecific antibodies are antibodies or antibody-like molecules having two different binding specificities. Because of this unique feature, bispecific antibodies not only connect therapeutics (e.g., T cells and drugs) with targets (e.g., tumors), but they can also block separate pathogenic mediators. Clinical successes and impressive treatment profiles against cancer, autoimmune diseases, and inflammatory diseases have been shown. See e.g., MAbs. 2009 November-December; 1(6): 539-547. Given their expanding therapeutic potential, the need for identifying new bispecific antibodies remains.